Process of case-hardening steel.



KIRK BLAKE,

OF LAPORTE,

IIJTDIANA.

PROCESS OF CASE-HARDENING STEEL.

No Drawing.

T 0 all whom it may concern:

Be it known that I, Kiln; BLAKE, a (itiZen of the United States, residing at Ilaporte, in the county of Laporte and State of Indi-- ana, have invented certain new and useful Improvements in Processes of CaseHardening Steel, of which the following is a spenfication.

This invention relates to a process of case hardening steel, through the chemical reaction of certain ingredients employed, said reaction being induced by heating the mass to a given temperature and maintaining said temperature for a period of time, and has for its object to render the process more efficient, expeditious and considerably cheaper.

The present method for case hardening steel, say, for instance, line shafts and material of similar character, is to take a number of the shafts and bury them in coarsely ground bone meal, the latter containing a sutlicient amount of natural carbon to impart to the steel a case of the desired thick ness, when the mass is placed into an oven and brought to and maintained at a temperature of 1750 Fahrenl'leit for a period of time ranging from 24 to 48 hours. The elliciency of the ground bone meal as a carbon producing medium is greatly impaired utter being subjected to the high temperature above noted, and, at present, in order to overcome the money loss that would result from discarding the residue of the bone meal, the same may be used at least once more by adding fresh bone meal, the amount added equaling about one-third of the mass. Adding the new bone meal together with the carbon remaining in the residue of the meal enriches the mass sutliciently to he used a second time. But this rebuilding of the residue of the bone meal cannot be carried on indefinitely from the fact that the prolonged heating readily extraets all the carbon and disintegrates the meal causing it Specification 0t Letters Patent.

Application filed March 6, 1912.

Patented Aug. 6, 1912.

Serial No. 682,042.

to be reduced to a tine dust with no carbon properties and hence unfit for further use.

The objeet of the present process is not only to rebuild the bone meal so as to enable it to be used many times but to reduce the time required to produce a case of the desired thickness in about one-half the time now consumed in doing the work.

To accomplish the above result I take bone meal of approximately the same amount as now used for a given job, say 90 pounds of steel; to this I add onet'ourth pound of cyanid of potassium: one quart of ammonia and 5 pounds of brown cane sugar, all of which are thoroughly mixed with the bone meal.

With the above mixture 1 have found by experimentation that I can provide a case of the same relative thickness in one-half the time now required, and an correspond ingly increase the thickness of the ease by correspondingly lengthening the time of baking.

I claim-- 1. The herein described composition of matter, consisting of bone meal, eyanid of potassium. ammonia, and brown cane sugar, substantially as described and for the purposes set forth.

Q. The herein described composition of matter for ease hardening steel. consisting of bone meal. of an amount sutlicient to embed ninety pounds of steel to be case hardened, one-fourth pound of eyauid of potassinm, one quart of ammonimand live pounds of brown cane sugar, substantially as de- .seribed.

In \\'itiless whereof, I. have hereunto set my hand and seat at Indianapolis, Indiana, this, 24 day of l ebrmiry, l\,. I). one thousand nine hundred and twelve.

KIRK BLAKE, [Lst \Vitnesses F. IV. \Vonuurn, L. B. Vtomcnmz. 

